I saw some screenshots of this game when doing the article on the R600 GPU's as they were included in all of the press marketing stuff from ATI.
Looking at their comparison between hl1, hl2 & TF2 - hl2 looked so much more realistic.
There's a more in-depth article on ign:
Is it just me or does it look cartoony and more like a cell-shaded game (like jetset radio etc)
seems a step backwards in terms of realism tbh.